According to the Economist more and more people are cutting the cord in the United States:
IF YOU want to save money, cut the cord. In these difficult times ever more Americans are heeding this advice and dropping their telephone landlines in favour of mobile phones (see article). Despite some of the flakiest mobile-network coverage in the developed world, one in four households has now gone mobile-only. At current rates the last landline in America will be disconnected sometime in 2025.
I cut the cord about a year ago. I had kept a landline to make international calls (everything else went over the cell phone), but Skype, the AT&T cell phone international calling plan, and the incessant public information messages from the city tipped me over the edge.
Two things popped out at me from the above paragraph, the first is that 25% of households are mobile only, a much higher number than I expected, and that the trend will be complete in 2025, which is only 16 years away.
Given that DSL/ADSL speeds have not kept up with those provided by cable and fiber, there would seem to be little point in investing in copper phone lines anymore.